As you can see there, is better to focus on HP[VIT in this case] then STR because it plays a higher role on the final dmg, 110-120 STR is enough for KS since HP gears are tons of time better then trying to get higher STR.

With the stats you've at the moment, you can still achieve a decent build that will end with 96 base VIT which will still hit 97 total VIT in the end that is anti-stun/silence which is still fine. The difference from 96 to 99 base vit isn't much to be that worried imo[it's like 100-200 difference dmg vs 50-60 def doing quick tests and this is ignoring % reduces] even if all the extra hp helps.

That dex isn't that bad too if you see the positive aspects of it, even if soul is already fast at max lv, that dex will make it faster to be cast even if not that needed.